Toggle main window hide on tray icon click

- converted openBictoinAction to toggleHideAction
- put GUIUtil functions into a namespace instead of a class
- put window-related functions together in optionsdialog

Reasoning:
- toggle is more typical behaviour
- it's more functional
- better UX

The typical issue with toggling visibility is that when a window
is obscured by other windows but in the 'shown' state, hiding it
isn't what you want. I've added an 'isObscured' function to GUIUtil
that checks several pixels in the window to see if they are visible
on the desktop so that an obscured but shown window can be raised.

Conflicts:

	src/qt/guiutil.cpp
	src/qt/guiutil.h

src/qt/guiutil.h

@@ -13,30 +13,29 @@ class QAbstractItemView;
 QT_END_NAMESPACE
 class SendCoinsRecipient;
 
-/** Static utility functions used by the Bitcoin Qt UI.
+/** Utility functions used by the Bitcoin Qt UI.
  */
-class GUIUtil
+namespace GUIUtil
 {
-public:
     // Create human-readable string from date
-    static QString dateTimeStr(qint64 nTime);
-    static QString dateTimeStr(const QDateTime &datetime);
+    QString dateTimeStr(const QDateTime &datetime);
+    QString dateTimeStr(qint64 nTime);
 
     // Render bitcoin addresses in monospace font
-    static QFont bitcoinAddressFont();
+    QFont bitcoinAddressFont();
 
     // Set up widgets for address and amounts
-    static void setupAddressWidget(QLineEdit *widget, QWidget *parent);
-    static void setupAmountWidget(QLineEdit *widget, QWidget *parent);
+    void setupAddressWidget(QLineEdit *widget, QWidget *parent);
+    void setupAmountWidget(QLineEdit *widget, QWidget *parent);
 
     // Parse "bitcoin:" URI into recipient object, return true on succesful parsing
     // See Bitcoin URI definition discussion here: https://bitcointalk.org/index.php?topic=33490.0
-    static bool parseBitcoinURI(const QUrl &, SendCoinsRecipient *out);
-    static bool parseBitcoinURI(QString uri, SendCoinsRecipient *out);
+    bool parseBitcoinURI(const QUrl &uri, SendCoinsRecipient *out);
+    bool parseBitcoinURI(QString uri, SendCoinsRecipient *out);
 
     // HTML escaping for rich text controls
-    static QString HtmlEscape(const QString& str, bool fMultiLine=false);
-    static QString HtmlEscape(const std::string& str, bool fMultiLine=false);
+    QString HtmlEscape(const QString& str, bool fMultiLine=false);
+    QString HtmlEscape(const std::string& str, bool fMultiLine=false);
 
     /** Copy a field of the currently selected entry of a view to the clipboard. Does nothing if nothing
         is selected.
@@ -44,7 +43,7 @@ public:
        @param[in] role    Data role to extract from the model
        @see  TransactionView::copyLabel, TransactionView::copyAmount, TransactionView::copyAddress
      */
-    static void copyEntryData(QAbstractItemView *view, int column, int role=Qt::EditRole);
+    void copyEntryData(QAbstractItemView *view, int column, int role=Qt::EditRole);
 
     /** Get save file name, mimics QFileDialog::getSaveFileName, except that it appends a default suffix
         when no suffix is provided by the user.
@@ -56,18 +55,20 @@ public:
       @param[out] selectedSuffixOut  Pointer to return the suffix (file type) that was selected (or 0).
                   Can be useful when choosing the save file format based on suffix.
      */
-    static QString getSaveFileName(QWidget *parent=0, const QString &caption=QString(),
+    QString getSaveFileName(QWidget *parent=0, const QString &caption=QString(),
                                    const QString &dir=QString(), const QString &filter=QString(),
                                    QString *selectedSuffixOut=0);
 
-
     /** Get connection type to call object slot in GUI thread with invokeMethod. The call will be blocking.
 
        @returns If called from the GUI thread, return a Qt::DirectConnection.
                 If called from another thread, return a Qt::BlockingQueuedConnection.
     */
-    static Qt::ConnectionType blockingGUIThreadConnection();
+    Qt::ConnectionType blockingGUIThreadConnection();
 
-};
+    // Determine whether a widget is hidden behind other windows
+    bool isObscured(QWidget *w);
+
+} // namespace GUIUtil
 
 #endif // GUIUTIL_H